The reverse and low reverse clutches are on in reverse. I would suspect the reverse clutches, fairly typical.
Do yourself a favor and install a Transgo Kit which will come with a heavier accumulator plate for the VB, but most importantly will come with a spring and ball to replace the converter limit valve assy in the pump which will be worn out.
Also, find a reputable trans shop to install an oversize switch valve plug assy in the VB, major wear there which will eventually kill the OD clutches.
Yes, it is coming out.